The present invention relates to a liquid container, and more particularly to a liquid container suitable for use as an ink cartridge having a plurality of ink chambers used for a color ink-jet printer.
As one type of liquid injectors for injecting a liquid onto a target, ink-jet type printers are in widespread use. This ink-jet type printer has a carriage and a recording head mounted on the carriage. The ink-jet type printer is adapted to effect printing with respect to printing paper by discharging ink from a nozzle formed in the recording head while moving the carriage relative to the recording medium. Further, in such an ink-jet type printer, an ink cartridge serving as a liquid container for storing ink is replaceably provided, and the ink discharged from the recording head is adapted to be supplied from the ink cartridge.
Patent document 1 discloses an ink cartridge storing a plurality of ink packs in a case. These ink packs respectively form a plurality of ink chambers. The ink packs are accommodated in the case such that a portion of the ink pack overlaps a portion of an adjacent ink pack, thereby reducing a dead space within the case.    Patent Document 1: JP-A-2003-53984
However, in the case where the plurality of ink packs are accommodated in one case in an overlapping manner as in the ink cartridge of patent document 1, one ink pack is brought into contact with an adjacent ink pack and a pressing action works. Since an ink bag making up the ink pack is formed of a flexible material such as a laminated film, such pressing affects the pressure of the ink accommodated in the ink pack. Accordingly, there is a problem in that a difference arises in the pressure of inks accommodated in the ink packs, i.e., the ink chambers.
Patent document 2 discloses an ink cartridge in which a single ink chamber is formed by attaching flexible plastic films to both sides of a flat rectangular frame made of a plastic plate by a method such as thermal welding. Films made of a soft plastic material are bonded or fused in a slack state to inner peripheral surfaces on both sides of the flat rectangular frame (peripheral walls of a housing) made of a plastic, to thereby form the ink chamber. The films are urged in an outward direction by a compression spring disposed inside this ink chamber to hold the pressure within the ink chamber under a negative pressure.    Patent document 2: JP-A-5-201019
With this ink cartridge, each flexible plastic film at its outer peripheral portion is attached to the rectangular frame in a slack state so that each flexible plastic film can move relative to the rectangular frame as the ink is consumed. A multiplicity of gathers are provided at the outer peripheral edge portion of the flexible plastic film, with the result that faulty sealing is likely to occur at the time of attaching the flexible plastic film to the rectangular frame by thermal welding or the like.
A primary object of the present invention is to provide a liquid container in which a plurality of liquid accommodating chambers formed by flexible films are arranged efficiently.
A secondary object of the present invention is to provide a liquid container which makes it possible to reduce to a low level a pressure difference among liquids accommodated in a plurality of liquid accommodating chambers formed by flexible films.
A tertiary object of the present invention is to provide a liquid container which has a plurality of liquid accommodating chambers air tightly sealed by flexible films.
It should be noted that, in the present invention, a flexible plastic film or a film made of rubber can be suitably used as the flexible film.